1. Field of the Invention
The invention is related to video tours, and more particularly to interactive video tours exploring remote real-world locations.
2. Description of the Related Art
Beginning with the “Movie maps” project by Lippman (A. Lippman, “Movie maps: An application of the optical videodisc to computer graphics,” Computer Graphics SIGGRAPH 1980, vol. 14 (3), July 1980, 32-43), there has been a series of systems for viewing video of remote locations. The Movie Maps project augmented images by virtual pointers to other information. By navigating towards a building in an image, for example, a user could select information attached to this building. More recent examples of virtual tour applications allow users to navigate panoramic video more seamlessly, giving users control over panning, tilting, zooming, and the direction of motion; see U.S. Pat. Nos. 6,968,973 and 7,096,428.
In 3-D video games, it is common to attach tags to objects in the scene that can be selected by users. For example, a tag may be a marked location on the surface of a rendered object, and by moving a cursor to this object the associated action may be invoked. These tags may also provide an alternative index into a virtual video game environment.
In virtual tour applications using panoramic images, providing such tags is difficult. This is because the true 3-D model of the imaged structure is generally unknown. Methods for recovering such structure generally require rich texture in the video stream, and only work well in stationary environments without moving objects. Further, existing image based 3-D reconstruction methods tend to be brittle in the presence of occlusion boundaries.
This motivates the creation of methods that facilitate the creation and display of tags in panoramic video, and the use of same within virtual tour applications.